NANO-ELECTRO-MECHANICAL
SYSTEM(NEMS)
CONTENTS
Introduction
 Benefits of Nano-machines
 Fabrication of NEMS device
 Advantages
 Applications
 Summary



INTRODUCTION
Nano-Electro-Mechanical
system
(NEMS)
is
the
integration of mechanical elements, sensors, actuators
and electronics on a common silicon substrate.

The Nano mechanical components are fabricated using
compatible “micromachining” process.

NEMS is the enabling technology allowing the
development of smart products.

Nano
electro
revolutionize
mechanical
measurements
devices
of
promise
extremely
to
small
displacement and extremely weak forces, particularly at
the molecular level.

NEMS devices can be so small that hundreds of them
can be fit in the same space as one single micro device
that performs same function.

In Nems devices the sensors gather the information from
surrounding
environment
through
measuring
mechanical, chemical, biological, chemical and optical
phenomenon.

The electronics then process the information derived
form the sensors.

Through some decision making capability direct the
actuators to respond by moving, regulating and filtering.


BENEFITS OF NANO MACHINES
Nano-Mechanical devices promise to revolutionize
measurements of extremely
small displacements and
forces.

Can built with the masses approaching a few
attograms(10-18g) and with the cross section of 10nm.

A second important attribute Nano machines is that they
dissipate less energy.

NEMS are extremely sensitive for the external damping
mechanisms which is crucial for building sensors.

The Geometry of a NEMS device can be tailored so that
the vibrating elements reacts only to external forces in a
specific direction.

NEMS are ultra low power devices.

Fundamental power scale is defined by the thermal
energy divided by the response time
 FABRICATION OF NEMS DEVICE
 There are three Basic building blocks in NEMS
technology.

Deposition processes.

Lithography.

Etching processes.
Deposition Process :

One of the basic building blocks in NEMS processing is
the ability to deposit thin films of materials.
 Thin
films of thickness of about few nm to about
100 nm.

Chemical methods used in NEMS deposition
process.
o Chemical vapour deposition.
o
Epitaxy.

Chemical vapour deposition :
Fig. 1: Typical hot-wall LPCVD reactor
 Epitaxy
:
Fig 2: Typical cold-wall vapour phase
epitaxial reactor
 Lithography

:
Lithography in the NEMS context is typically the
transfer of a pattern to a photosensitive material by
selective exposure to a radiation source such as light.

A photosensitive material is a material that experiences a
change in its physical properties when exposed to a
radiation source.

Pattern Transfer :
Fig 3: Transfer of a pattern to a photosensitive material

Figure 4:a) Pattern definition in positive resist, b) Pattern definition in
negative resist.

Alignment :

Inorder to make useful devices the patterns for different
lithography steps that belongs to a single structure must
be aligned to one another.


The first pattern includes a set of alignment marks.
The first pattern alignment marks used as the reference
when positining subsequent patterns.

Exposure :

This parameter is required in order to achive accurate
pattern transfer from the Mask to the photo sensitive
layer.

Different Photo resist exhibit different sensitivity to
different wavelengths
 Etching
 It
:
is necessary to etch the thin films previously
deposited or the substrate itself.
 There
are 2 class of etching process.

Wet etching.

Dry etching.

Wet etching :

This is the simplest etching technology.

There are complications since usually Mask is desired to
selectively etch the material.

It requires a container with a liquid solution that dissolve
the material used.

Some single crystall material, such as silicon, exhibits
anistropic etching in certain chemicals.
 ADVANTAGES
o
Cost effectiveness.
o
System integration.
o
High Precision.
o
Small size.
 APPLICATIONS

OF NEMS
Accelerometer :
NEMS
accelerometers
conventional
are
accelerometers
quickly
for
deployment systems in automobiles.
Figure 6 : Accelerometer(air bags)
crash
replacing
air-bag

Nano nozzles:

Another wide deployment of NEMS is their use as nano
nozzles that direct the ink in inkjet printers.

They are also used to create miniature robots (nano-
robots) as well as nano-tweezers.

NEMS have been rigorously tested in harsh
environments for defense and aerospace where they are
used as navigational gyroscopes.

NEMS in Wireless :

A 3G “smart” phone will require the functionality of as
many as five
radios – for TDMA, CDMA, 3G,
Bluetooth and GSM operation. A huge increase in
component count is required to accomplish this demand.

Thermal actuator :

Thermal actuator is one of the most important NEMS
devices, which is able to deliver a large force with large
displacement.
 SUMMARY

Nano-systems have the enabling capability and potential
similar to those of nano-processors .

Since NEMS is a nascent and synergistic technology,
many new applications will emerge, expanding the
markets beyond that which is currently identified or
known.

NEMS is forecasted to have growth similar to its parent
IC technology.

For a great many applications, NEMS is sure to be the
technology of the future.
THANK YOU